We were in a similar situation. We loved our nanny and paid her well, fed holidays off, she was paid when we went on holiday and she received 2 weeks paid vacation.
Needless to say, I could tell there was some resentment. Nothing ever seemed good enough. I always felt like I was just trying to please her. It got very uncomfortable.
Here's the problem, we both hired nannies before really understanding all of the details. I have only myself to blame for not putting everything in black and white and being very upfront about future salary.
Ultimately we parted ways-- on good terms. While we miss her terribly, it was a much needed break. We appreciate her more and I think she feels the same. We still see her and love her. She still babysits on occasion.
Long story short, if it's in the best interest of both parties, start over. You can help her find a good paying job on DCUM. It's an uncomfortable topic but if you can sit down and talk it through, you will most likely have your answer.
Good luck and remember, it's a learning process.